退火对镁阳极氧化涂层结构与耐腐蚀性能的影响

Effect of annealing on structure and corrosion resistance of magnesium anodized coating

摘要:

目的：通过阳极氧化及退火处理对镁表面氧化膜层进行优化并探索其对镁表面氧化层结构、耐腐蚀性能以及生物相容性的影响。方法：对纯镁进行不同电压参数的阳极氧化（5V、10V、20V、40V），后进行450℃高温退火处理。通过扫描电子显微镜分析膜层表面及截面形貌，原子力显微镜分析三维结构与粗糙度，电化学极化实验与体外浸泡实验评估耐腐蚀性能，CCK-8实验评估对小鼠成骨细胞MC3T3-E1的增殖活性影响。结果:电压的升高可以使表面膜层从层板状变得多孔，继续升高又变得光滑均匀。退火处理维持了基本形貌特征，膜层厚度有所增加，粗糙度有所下降。未退火膜层由于微孔的存在以及氢氧化镁的不稳定导致耐腐蚀性能并未增高，退火所形成的致密氧化镁结晶膜层有一定的保护作用，其中40V氧化后退火组拥有相对较好的耐腐蚀性能，且对细胞增殖无明显抑制作用。结论：阳极氧化电压对纯镁阳极氧化膜层结构有影响，退火可以进一步稳定膜层，提高其耐腐蚀性能，40V氧化退火组耐腐蚀性能较好，且生物相容性良好。

Abstract:

Objective: To optimize the anodized film on the magnesium surface and explore its effect on the structure,corrosion resistance and biocompatibility through anodizing and annealing treatments.Methods: Pure magnesium was anodized with different voltage parameters (5V, 10V, 20V, 40V), and then annealed at high temperature. The surface and cross-section morphology of the coatings formed were analyzed by scanning electron microscopy.Three-dimensional structure and roughness were analyzed by atomic force microscope. The corrosion behavior of each group of samples was evaluated by electrochemical polarization experiments and in vitro immersion test.The proliferation activity of mouse osteoblasts MC3T3-E1 was evaluated by the CCK-8 method. Results: The increase of the voltage can make the surface coating become porous from the lamellar shape, and then continue to increase voltage，the layer become smooth and uniform. The annealing treatment maintained the basic morphological characteristics, the coating thickness increased and the roughness decreased.The corrosion resistance of the unannealed coating does not increase due to the existence of micropores and the instability of magnesium hydroxide. The dense magnesium oxide crystalline coating formed by the annealing has a certain protective effect. The 40V post-oxidation annealing group has relatively good corrosion resistance and has no obvious inhibitory effect on cell proliferation.Conclusion: Voltage affects the structure of anodized coating. Annealing can further stabilize the coating and improve its corrosion resistance.The 40V post-oxidation annealing group has a better corrosion resistance and biocompatibility .